His problem was to get from Lookout Valley to Chattanooga Valley in the most expeditious way possible; cross the latter valley rapidly to Rossville, south of Bragg's line on Missionary Ridge, form line there across the ridge facing north, with his right flank extended to Chickamauga Valley east of the ridge, thus threatening the enemy's rear on that flank and compelling him to reinforce this also.

Thomas, with the Army of the Cumberland, occupied the centre, and was to assault while the enemy was engaged with most of his forces on his two flanks.
To carry out this plan, Sherman was to cross the Tennessee at Brown's Ferry and move east of Chattanooga to a point opposite the north end of Mission Ridge, and to place his command back of the foot-hills out of sight of the enemy on the ridge.

There are two streams called Chickamauga emptying into the Tennessee River east of Chattanooga--North Chickamauga, taking its rise in Tennessee, flowing south, and emptying into the river some seven or eight miles east; while the South Chickamauga, which takes its rise in Georgia, flows northward, and empties into the Tennessee some three or four miles above the town.
There were now one hundred and sixteen pontoons in the North Chickamauga River, their presence there being unknown to the enemy.
At night a division was to be marched up to that point, and at two o'clock in the morning moved down with the current, thirty men in each boat.

A few were to land east of the mouth of the South Chickamauga, capture the pickets there, and then lay a bridge connecting the two banks of the river.

The rest were to land on the south side of the Tennessee, where Missionary Ridge would strike it if prolonged, and a sufficient number of men to man the boats were to push to the north side to ferry over the main body of Sherman's command while those left on the south side intrenched themselves.